Pre-fab chimney height near existing brick chimney

[Fieldborntemple]

I understand the requirement for chimney hight is 3' above point of passage through roof and 2' taller than structure in a 10' radius.

My question is this: My existing brick chimney has multiple flues within it. Is there any reason I can't run my pre-fab triple-wall chimney up along my existing brick chimney about 6" away, and then terminate around the same height (so long as the 3' 2' 10' rule is otherwise met)?

I can't find a specific answer anywhere online. Is this matter addressed in a code book anywhere?

I get the feeling the 2' 3' 10' rule still applies although it would be frustrating because my existing brick chimney has multiple flues and those are still built that way today without violating any kind of building code.

Thanks for any input!

 

[kennyp2339]

You will have to go slightly higher to fit the cap on, also there is a chance that one of the existing flue's gets a down draft (normal) and it may suck the smoke from the other chimney down it, making a smoky smell in the house.

 

[begreen]

Yes, if this is going to be the primary wood burning device then I'd put the top of the class A chimney pipe about 1ft. higher than the other flues to reduce the possibility of smoke getting sucked down one of the other flues and into the house.

 

[Fieldborntemple]

Thanks folks!

This photo is the result. (The existing chimney has been re-pointed, it just isn't nicely straight/even, but it is solid.)

We'll see what Mr Home Owners Insurance man says when I report to them my completed and operational installation...